Spit starts out about as salty as blood. As it flows down little tubes, stripy cells pull out much of the salt before it reaches your mouth.
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Spit is made in little round pockets inside your salivary glands. Then it travels through tiny tubes, called ducts, toward your mouth.
Some of these tubes are lined with tall cells that have stripes along their bottom edge. Scientists call them striated, which just means striped.
The stripes are deep folds in the cell's skin, packed with mitochondria, the cell's power makers.
Pumping takes a lot of energy. That's why these cells need so many power makers.
Press Pump the salt on the 3D model to see salt leave the spit tube.
Each striped cell can have lots of mitochondria lined up in rows. Under a microscope, they look like the teeth of a comb!